integrx

Setup: 96 Auto LS with 15g, SMC, DSM 450, ebay BOV, tyrus IC, 2.5" dp-testpipe-back to muffler, no boost controler.
From turbo, 2" to 2" 90degree bend, then after is 2.5" bends to IC and AEM used as other piece to intake mani. There is a 3/8" cap for the AEM to valve cover and its tight.
boost gaauge tee off fpr, bov tee off brake booster, zip tied all connections.

So on a freeway pull its not holding boost at WOT. When i floor it, it climbs to about 6 then drops down to 4. Why? I thought it was the BOV leaking, but...
When its 3/4 throttle it can hold at 8psi at 4k rpm.
Another problem is after the pulls i can now hear my BOV when still in vaccum and the car shifts, i even tightened it and ran it again. Same thing not holding boost, and can hear BOV when still in vaccum. Why?
Another thing is when i was done and pulling into my parking lot I throw a CEL, i think its because of the testpipe, although i will check for the code tomorrow.
I bought the turbo used, but i think the previous owner did the wastegate nut trick to boost more. It should be set at about 8. I don't think its spiking to 8. It slowly climbs and stays there when part throttle.

for those who want to know the whole set-up i also have NGK bkre7, MSD SCI w/ ss blaster coil. SMC was runing on the rich side (it was cold outside) it was at .95-.96 volts


Modified by integrx at 5:09 AM 1/28/2004


Modified by integrx at 1:03 PM 1/28/2004

GDM Z28

my ls does the same damn thing. on WOT it will hold 10 in some gears and in others it slowly drops to 8

integrx

what turbo you have?
https://honda-tech.com/zerothread?id=570268
that is someone with a 15g in a bseries.

GDM Z28

i have a t3 50 trim, .48 ext

integrx

maybe i need a mbc, and adjust the nut back to the center?

GDM Z28

i dont know i am using a mbc and it does it for me 2

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integrx &raquo;</TD></TR><TR><TD CLASS="quote">maybe i need a mbc, and adjust the nut back to the center?</TD></TR></TABLE>

Try it. The MBC is a MUCH better way to control boost than adjusting the actuator rod. Changing the length of the rod either adds preload, which limits the amount the wastegate can open, or opens it prematurely, slowing down spool.

You want to set the rod so that it barely fits over the wastegate arm, and then use a MBC.

integrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">
You want to set the rod so that it barely fits over the wastegate arm, and then use a MBC.
</TD></TR></TABLE>
When your saying that should the the nut be adjusted towards the wastegate or away from the wastegate?

integrx

hey can one of the people with more "Knowledge" tell me if the greddy 15G is just plain too small of a turbo for a b18b.

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integrx &raquo;</TD></TR><TR><TD CLASS="quote">
When your saying that should the the nut be adjusted towards the wastegate or away from the wastegate? </TD></TR></TABLE>

Whichever way you need to adjust it so that there is a tiny bit of tension in the spring when you slip it on.

The 15g isn't too small to hold 8 psi, no way.

integrx

but is the 15g too small for a b-series (b18b) to hold 8psi intercooled

integrx

Greddy TD04H-15G turbo 260hp max i guess.
Compressor 53mm, 41.2mm
Turbine 52mm, 44.2mm

now who can help me calculate it?

integrx

GOT THIS OFF A WEBSITE

adjust the amount of spring force in the waste gate valve to limit the full load boost pressure! This is the most stupid way to try to get more power, because 99% of the LET turbochargers get badly damaged after some time. The valve seat of the waste gate valve breaks into pieces and results in the Waste Gate not holding pressure and leaves the spring power the actuator doing the rest. So, most importantly the full load boost pressure is decreasing more and more, when the user now tries to make only the spring of the waste gate valve stronger by adjusting the waste gate tread , he will get the following problem : The overboost will rise up to 1.6 to 1.8 bar at low engine speed (3500-4000), the engine can be damaged very quickly , and at full engine speed there is only 0.7 bar available . This engine is driving very bad, there is only one big push at 4000 rpm. After this point with rising engine speed, the boost pressure is falling constantly, so the engine output power is near constant at rising engine speed and the drivability of this engine is very bad!!

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integrx &raquo;</TD></TR><TR><TD CLASS="quote">but is the 15g too small for a b-series (b18b) to hold 8psi intercooled</TD></TR></TABLE>

I ******* ANSWERED THIS ALREADY. SERIOUSLY.

It's not too small. You have other problems.

slowpokin699

sounds wategate related.... just go to home depot racing and get a mbc and see what happens..

integrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">

I ******* ANSWERED THIS ALREADY. SERIOUSLY.

It's not too small. You have other problems.
</TD></TR></TABLE>

gezz, talking about getting upset. You said no way the 15g is not too small to hold 8psi
but you know different size engine does make a difference. sorry just had to get that out there. chill

slowpokin699

yeah, diffrences in spool times not peak hold boost!

GDM Z28

get a EBC it will hold you at the set psi

Flamenco-T

are you sure that there are no leaks from the IC pipes, Intercooler and etc ?

stan